Synthesis of Fe 2 SiO 4 -Fe 7 Co 3 Nanocomposite Dispersed in the Mesoporous SBA-15: Application as Magnetically Separable Adsorbent

• Published in: Molecules (Basel, Switzerland) Vol. 25; no. 4
• Main Authors: da Silva, Monickarla Teixeira Pegado, Barbosa, Felipe Fernandes, Morales Torre, Marco Antonio, Villarroel-Rocha, Jhonny, Sapag, Karim, Pergher, Sibele B C, Braga, Tiago Pinheiro
• Format: Journal Article
• Language: English
• Published: Switzerland 24.02.2020
• Subjects: Adsorption; Alloys - chemistry; Azo Compounds - isolation & purification; Coloring Agents - isolation & purification; Humans; Iron - chemistry; Kinetics; Methylene Blue - isolation & purification; Nanocomposites - chemistry; Rhodamines - isolation & purification; Silicon Dioxide - chemistry; Water Pollutants, Chemical - isolation & purification; Water Purification - methods; adsorption; magnetic nanocomposite; Fe2SiO4 oxide; Fe7Co3 alloy; dyes

The mixture containing alloy and oxide with iron-based phases has shown interesting properties compared to the isolated species and the synergy between the phases has shown positive effect on dye adsorption. This paper describes the synthesis of Fe SiO -Fe Co -based nanocomposite dispersed in Santa Barbara Amorphous (SBA)-15 and its application in dye adsorption followed by magnetic separation. Thus, it was studied the variation of reduction temperature and amount of hydrogen used in synthesis and the effect of these parameters on the physicochemical properties of the iron and cobalt based oxide/alloy mixture, as well as the methylene blue adsorption capacity. The XRD and Mössbauer results, along with the temperature-programmed reduction (TPR) profiles, confirmed the formation of Fe SiO -Fe Co -based nanocomposites. Low-angle XRD, N isotherms, and TEM images show the formation of the SBA-15 based mesoporous support with a high surface area (640 m /g). Adsorption tests confirmed that the material reduced at 700 °C using 2% of H presented the highest adsorption capacity (49 mg/g). The nanocomposites can be easily separated from the dispersion by applying an external magnetic field. The interaction between the dye and the nanocomposite occurs mainly by π-π interactions and the mixture of the Fe SiO and Fe Co leads to a synergistic effect, which favor the adsorption.